A system for fire protection using recirculation of combustion products

ABSTRACT

A system for fire protection wherein a nozzle discharges an extinguishant in response to a predetermined fire condition in a manner to create an aspiration effect which circulates the combustion products from the fire in a path including the fire. The circulation of the combustion products is terminated and the rate and manner of discharge of extinguishant from the nozzles can be changed in response to an additional predetermined fire condition.

United States Patent 1 1 Yao 4 1 Jan. 2, 1973 s41 SYSTEM FOR FIRE PROTECTION 3,407,880 10/1968 Davis 169/12 USING RECIRCULATION OF 3,463,234 8/1969 Van Baak..... ..l69/l2 x COMBUSTION PRODUCTS E A" N K I Primary xamineren now es [75] Inventor C s Mass Assistant Examiner-John J. Love [731' Assignee: Factory Mutual Research Corporh- Attorney-Joseph M. Lane et a].

tion, Norwood, Mass. I 22 Filed: Nov. 12,1971 [57] ABSTRACT [21] APPL No 198,386 system for tire protection wherein a nozzle discharges an extinguishant 1n response to a predetermined fire condition in a manner to create an aspira- [52] US. Cl. 169/12, 169/41, 169/42 tion effect which circulates the combustion products [51] II.- Cl ..A62C 35/52 from the fire in a path including the fire The circu|a Fleld of Search n-169,12, 37, 38, 41, i of the combustion products is terminated and the rate and manner of discharge of extinguishant from 5 References cued the nozzles can be changed in response to an addi- UNITED STATES PATENTS tional predetermined fire condition. 2,498,512 2/1950 Thompson ..169/l2 l9 Clail ns, 3 Drawing Figures PATENTEDm 2 ms 3,708,015

F/6./. FIG. 3.

INVENTOR C H E N 6 YA 0 WW rlmd ATTORNE Y3 SYSTEM FOR FIRE PROTECTION USING RECIRCULATION OF COMBUSTION PRODUCTS CROSS REFERENCE TO RELATED APPLICATION This application relates to US. Pat. Application Ser. No. 131,988 filed on Apr. 7, 1971, by the same inventor as the present invention and assigned to the same assignee as the present invention. The disclosure of the latter application is hereby incorporated by reference.

BACKGROUND OF THE INVENTION This invention relates to a system for fire protection, and more particularly to such a system which utilizes the products of combustion from a fire to aid in extinguishing the fire. The system includes a discharge device and method for achieving the above.

In the above-mentioned related application, a fixed fire extinguishing system is disclosed in which the combustion products of a fire developing in the enclosure to be protected are circulated back towards the fire at the early stage of the fire development to prevent the ingress of air to the fire. The circulation of the combustion products is achieved by the use ofaplurality of aspiration-type nozzles which are mounted near the ceiling of the enclosure, with each having an inlet opening for receiving the products of combustion and a discharge opening for discharging the products of combustion. When actuated, the nozzles discharge an extinguishant towards the fire which creates an aspiration effect and circulates the products of combustion in a path upwardly from the fire, through the nozzles, and downwardly into the fire. In this manner, air entering the building through its windows and doors and passing towards the fire is blocked by the barrier created by the products of combustion.

Although the above arrangement was found to be effective in extinguishing fires, it suffered from the fact that the extinguishant discharge velocity from the nozzles had to be set at a relatively high value in order to obtain the aspiration effect. Since this was accomplished by utilizing a relatively small discharge opening, the extinguishant discharge from the nozzles was ineffective in directly fighting the fire, since it was unable to penetrate the fire plume. This, of course, imposed limitations on the fire-fighting capability of the system. especially in fire situations in which the recirculation of the combustion products around the fire could not achieve total fire extinction.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a system of the above type in which the com bustion products from the fire are circulated in a path including said fire, with the circulation being terminated locally in response to additional information received from the fire.

It is a further object of the'present invention to provide a system for fighting a fire in which the rate and manner of discharge from the nozzles is altered upon the termination of the circulation of the combustion products.

Towards the fulfillment of these and other objects of the present invention, the system of the present invention comprises at least one nozzle, means responsive to a predetermined fire condition for permitting the discharge of extinguishant from said nozzle, means responsive to the-discharge of extinguishant from said nozzle for circulating the combustion products from said fire in a path including said fire, and means responsive to an additional predetermined fire condition for reducing said circulation and for changing the rate and manner of said discharge.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 2'is a crosssectional view taken along the line 2-2 of FIG. 1; and

FIG. 3 is a view similar to FIG. 1, but showing the device of the present invention after responding to a fire condition.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The discharge device of the present invention is depicted in FIG. 1 of the drawings, and includes a nozzle unit 10 defining a discharge outlet 10a at its lower end as viewed in FIG. 1 and having a T-shaped coupling member 12 threadably connected to its upperfend. One end portion of the coupling member 12 is internally threaded as shown at for connection to a branch line 13 for supplying an extinguishant such as water, it being understood that a typical fire protection system will include several discharge devices and branch lines, along with submains, risers, and a main, to supply the branch lines with an extinguishant, such as water, in a conventional manner, and as shown and described in the above-mentioned related application.

A closure plug 14 is threadably engaged in the other end portion 12b of the coupling member 12 and defines a central opening which receives a valve stem 16 slidably extending therethrough. A valve head 18 is connected to one end of the valve stem 16 and is adapted to engage a cooperating seat 20 supported by the internal wall of the coupling member 12 to block the flow of extinguishant .through the coupling member.

A lever arm 22 is pivotally mounted to the plug 14 and is adapted to be connected, by means of a fusible link 24, to a lever arm 26 fixed withrespect to the plug. The pivotal lever arm 22 has a projection engaging the other end of the valve stem 16 to maintain the valve head 18 against the seat 20 as long as the fusible link 24 maintains the connection between the levers 22 and 26.

A pair of vanes, shown in general by the reference numeral 32, are provided in the interior of the nozzle unit 10 in order to impart a swirling-type motion to the extinguishant as it passes through the nozzle unit, thereby resulting in a continuous conical spray discharge from the discharge outlet 10a, in a conventional manner.

A circumferential groove 34 is formed in the outer periphery of the nozzle unit 10 for reasons that will be explained in detail later.

the discharge outlet a, with the opening 42a being of a smaller diameter than the outlet 10a. In an exemplary embodiment of the present invention, the outlet 100 would havea diameter of approximately one-half inch and would discharge the extinguishant at a spray angle of approximately 150, while the opening 42a would have a diameter of approximately one-eighth of an inch and would discharge the extinguishant at a spray angle of approximately 100.

The housing 40 is connected relative to the nozzle unit 10 by means of three substantially L-shaped connecting arms 50. Each of thearms 50 consists of a lower portion 50a which engages underneath an inwardly-directed circular flange 400 formed on the upper end of the housing 40, and an upper portion 50b which engages a split ring 52 extending around the upper end portion of the nozzle unit 10 and having its ends normally connected by a fusible link 54. The elbow portions of the arms 50 are supported by, and extend within, the circumferential groove 34.

Referring specifically to FIGS. 1 and 2 for a better view of the interconnection between the upper arm portions 50b and the ring 52, it is seen that the arm portions are curved slightly at their upper ends so that they extend around, and over, the top surface of the ring. in this manner the ring 52 can be designed to maintain the arms 50 under a slight, inwardly-directed spring tension in order to maintain the arms, and therefore the housing 40, in the position shown in FIG. 1. Of course, when the link 54 fuses in response to a predetermined temperature, the ends of the ring are free to separate, which will release the arms 50 and therefore permit the housing 40 to fall from the nozzle 10 under the force of gravity.

The temperatures required to fuse the fusible link 24 and the fusible link 54 may vary in accordance with particular design considerations. A preferred embodiment would have the fusible link 54 adapted to fuse at a temperature greater than the fusible link 24, with a specific example of the fusing temperatures being 165F. for the link 24 and 500F. for the link 54.

As an example of the operation of the discharge device of the present invention and using water as an I example of the extinguishant, upon the temperature in the, vicinity of the fusible link 24 reaching 165F., the link will collapse and permit a pivoting of the arm 22 relative to the arm 26 under the force of the valve stem 16 as a result of the water pressure acting against the valve head 18. This permits the valve head 18 to unseat from the seat 20 and extinguishant to flow into and through the nozzle unit 10. The resulting discharge of the water from the device will be at a relatively high velocity, a relatively low rate, and a relatively narrow spray angle due to the presence of the relatively small discharge opening 42a provided by the extension 42. This relatively high velocity is sufficient to induce the products of combustion from the fire to enter the housing 40 through its inlet 400. This, plus the venturi shape of the housing 40, creates an aspiration effect which circulates the products of combustion from the fire in a path from the fire, downwardly through the inlet 40a, and outwardly from the housing through the outlet 40b.-

in this action the water is atomized into a fog, a large portion of which circulates with the combustion products in the above manner. As emphasized in the above-cited application, this circulation of the combustion products creates a barrier which prevents air entering the building through doors, windows, etc., from passing directly into the fire. As a result, the fire will be smothered and rendered relatively easy to extin- I guish.

' In the event the above circulation of combustion products does not completely extinguish the fire, and assuming the fire causes the temperature in the vicinity of the device to increase to approximately 500F., the fusible link 54 will collapse, permitting a release of the split ends of the ring 52 and a release of the arms 50 from the ring. The housing 40 will thus be released from the position shown in FIG. 1 and will fall away from the nozzle unit 10. As a result, the device will take theoperational position shown in FIG. 3, with the extinguishant flowing directly into the nozzle unit 10 and being directly discharged from the relatively large outlet 10a at a relatively high rate and wide spray angle.

Thus, in the latter operational mode of the device, the above-mentioned aspiration effect will be eliminated and the rate of extinguishant discharge and the area of coverage will be increased.

Of course, in a system' incorporating several of the discharge devices, it is apparent that, in a typical high-- challenge fire situation, the discharge devices directly over the fire may attain their direct discharge mode while the peripheral devices will circulate the combustion products in the above manner. As a result the former devices will have a relatively good chance of extinguishing the fire directly since the latter devices will prevent the ingress of air to the fire. As a result, op timum fire fighting capability is achieved.

it is understood that the invention is not limited to the use of water as an extinguishant, but can incorporate other extinguishants that lend themselves to the above operation. For example, a water based foam forming fluid may be used in accordance with the foregoing. An example of the latter would-be a mixture of water and a foaming compound such as any one of a number of synthetic surface active agents that are stable with the fire products of combustion. The foaming compound could be injected into the waterline in response to a fire situation and the resulting fluid, when discharged through the outlet 42a in accordance with the foregoing, would create the aspiration effect discussed above and induce the products of combustion into the housing 40. The resulting mixture of the solution and the combustion products would cause the foaming compound to foam, with the compound preferably being such that the resulting foam would consist of between ZOO-1,000 parts combustion products to 1 part of water by volume. Of course, upon the fusing of the links 54 and the resulting release of the surized would discharge directly to the fire in a spray of droplets with the water functioning as an extinguishant, as discussed above.

Other examples of extinguishants that may be used in the present invention are gaseous agents such as pres- I nitrogen, carbon dioxide, halogenated hydrocarbon agents such as freon, or other similar gases, as discussed in detail in the above-meritionedapplication.

It is understood that several other variations may be made in the foregoing without departing from the scope of the invention. For example, the detector system disclosed in the above-mentioned related application and adapted to reduce the rate of discharge provided to each nozzle after a predetermined time delay, can be incorporated in the system of the present invention. Also, the sizes of the outlet a and the opening 42a, as well as the fusing temperatures for the links 24 and 54, may be varied in accordance with the present invention.

Still other variations of the specific construction and arrangement of the discharge device and method disclosed above can be made by those skilled in the art without departing from the invention as defined in the appended claims.

I claim:

1. A discharge device for fire extinguishant, comprising a nozzle, first means responsive to a predetermined fire condition for permitting the discharge of extinguishant from said nozzle, second means responsive to the discharge of extinguishantfrom said nozzle for circulating the combustion products from said fire-in a path including said fire, and third means responsive to an additional predetermined fire condition for terminating said circulation while maintaining said discharge.

2. The device of claim 1 wherein said second means comprises a housing extending over and connected to a portion of said nozzle, said housing being in the form of a venturi having an inlet and an outlet for receiving and discharging said combustion products, respectively, the discharge from said nozzle creating an aspiration effect to cause said'circulation through said housing.

3. The device of claim 2 wherein said third mans comprises fusible means connecting said housing to said nozzle and adapted to fuse in response to said additional predetermined fire condition and break said connection.

4. The device of claim 2 wherein said third means comprises an extension for said outlet, said extension defining an opening registering with said outlet and having a smaller diameter than the diameter of said outlet, and means connecting said extension to said housing.

5. The device of claim 4 wherein said third means further comprises fusible means connecting said housing to said nozzle and adapted to fuse in response to said additional predetermined fire condition and. break said connection, whereby said rate of discharge is increased.

6. The device of claim 1 wherein the first predetermined fire condition is a predetermined temperature in the vicinity of said nozzle and said additional predetermined fire condition is a' temperature in the vicinity of said nozzle greater thansaid predetermined temperature.

7. The device of claim 1 wherein said extinguishant is a foam forming fluid wherein said second means is adapted to mix said fluid and said combustion products in a manner to foam said fluid, and wherein, upon said termination of said circulation, said nozzle is adapted to discharge said fluid directly towards said fire in a spray of droplets without forming said foam.

8. The device of claim 1 wherein said extinguishant is water, wherein said second means is adapted to mix said water and said combustion products in a manner to atomize said water and form a fog, and wherein, upon said termination of said circulation, said nozzle is adapted to discharge said water directly towards said fire in a spray of droplets without forming said fog.

9. The device of claim 1 wherein said extinguishant is a gaseous agent.

10'. The device of claim 1 wherein said third means also changes the spray angle of said discharge.

11. The device of claim 1 wherein said third means changes the rate of said discharge in response to said additional predetermined fire condition.

12. A fire protection system comprising a plurality of discharge heads mounted in an elevated position in the space to be protected and adapted for connection to a source of extinguishant, first means responsive to a predetermined fire condition for permitting the discharge of extinguishant from at least one of said heads, second means responsive to the discharge of extinguishant from said heads for circulating the combustion products from said fire in a path including said fire, and third means responsive to an additional predetermined fire condition for reducing said circulation'while maintaining said discharge.

13. The system of claim 12 wherein the first predetermined fire condition is a predetermined temperature in the vicinity of each of said heads and said additional predetermined fire condition is a temperature in the vicinity of each of said heads greater than said predetermined temperature.

14. The system of claim 13 wherein each of said heads individually circulates the combustion products from said fire in response to said predetermined temperature and wherein each of said heads individually terminates said circulation and discharges the extinguishant at a different rate in response to said greater temperature.

15. The system of claim 14 wherein said circulation is reduced by at least a portion of said heads terminating its respective circulation, while the remaining heads continue their circulation.

16. The system of claim 12 wherein said extinguishant is a foam forming fluid, wherein said second means is adapted to mix said fluid and said combustion products in each of said heads in a manner to foam said fluid, and wherein, upon said reduction of said circulation, each of said heads is adapted to discharge said fluid directly'towards said fire in a spray of droplets without forming said .foam.

17. The system of claim 12 wherein said extinguishant is water, wherein said second means is adapted to mix said water and said combustion products in each of said heads in a manner to atomize.

said water and form a fog, and wherein, upon said reduction of said circulation, each of said heads is adapted to discharge said water directly towards said fire in a spray of droplets without forming said fog.

18. The system of claim 12 wherein said third means also changes the spray angle of said discharge.

19. The system of claim 12 wherein said third means changes the rate of said discharge in response to said additional predetermined fire condition. 5 

1. A discharge device for fire extinguishant, comprising a nozzle, first means responsive to a predetermined fire condition for permitting the discharge of extinguishant from said nozzle, second means responsive to the discharge of extinguishant from said nozzle for circulating the combustion products from said fire in a path including said fire, and third means responsive to an additional predetermined fire condition for terminating said circulation while maintaining said discharge.
 2. The device of claim 1 wherein said second means comprises a housing extending over and connected to a portion of said nozzle, said housing being in the form of a venturi having an inlet and an outlet for receiving and discharging said combustion products, respectively, the discharge from said nozzle creating an aspiration effect to cause said circulation through said housing.
 3. The device of claim 2 wherein said third mans comprises fusible means connecting said housing to said nozzle and adapted to fuse in response to said additional predetermined fire condition and break said connection.
 4. The device of claim 2 wherein said third means comprises an extension for said outlet, said extension defining an opening registering with said outlet and having a smaller diameter than the diameter of said outlet, and means connecting said extension to said housing.
 5. The device of claim 4 wherein said third means further comprises fusible means connecting said housing to said nozzle and adapted to fuse in response to said additional predetermined fire condition and break said connection, whereby said rate of discharge is increased.
 6. The device of claim 1 wherein the first predetermined fire condition is a predetermined temperature in the vicinity of said nozzle and said additional predetermined fire condition is a temperature in the vicinity of said nozzle greater than said predetermined temperature.
 7. The device of claim 1 wherein said extinguishant is a foam forming fluid wherein said second means is adapted to mix said fluid and said combustion products in a manner to foam said fluid, and wherein, upon said termination of said circulation, said nozzle is adapted to discharge said fluid directly towards said fire in a spray of droplets without forming said foam.
 8. The device of claim 1 wherein said extinguishant is water, wherein said second means is adapted to mix said water and said combustion products in a manner to atomize said water and form a fog, and wherein, upon said termination of said circulation, said nozzle is adapted to discharge said water directly towards said fire in a spray of droplets without forming said fog.
 9. The device of claim 1 wherein said extinguishant is a gaseous agent.
 10. The device of claim 1 wherein said third means also changes the spray angle of said discharge.
 11. The device of claim 1 wherein said third means changes the rate of said discharge in response to said additional predetermined fire condition.
 12. A fire protection system comprising a plurality of discharge heads mounted in an elevated position in the space to be protected and adapted for connection to a source of extinguishant, first means responsive to a predetermined fire condition for permitting the discharge of extinguishant from at least one of said heads, second means responsive to the discharge of extinguishant from said heads for circulating the combustion products from said fire in a path including said fire, and third means responsive to an additional predetermined fire condition for reducing said circulation while maintaining said discharge.
 13. The system of claim 12 wherein the first predetermined fire condition is a predetermined temperature in the vicinity of each of said heads and said additional predetermined fire condition is a temperature in the vicinity of each of said heads greater than said predetermined temperature.
 14. The system of claim 13 wherein each of said heads individually circulates the combustion products from said fire in response to said predetermined temperature and wherein each of said heads individually terminates said circulation and discharges the extinguishant at a different rate in response to said greater temperature.
 15. The system of claim 14 wherein said circulation is reduced by at least a portion of said heads terminating its respective circulation, while the remaining heads continue their circulation.
 16. The system of claim 12 wherein said extinguishant is a foam forming fluid, wherein said seCond means is adapted to mix said fluid and said combustion products in each of said heads in a manner to foam said fluid, and wherein, upon said reduction of said circulation, each of said heads is adapted to discharge said fluid directly towards said fire in a spray of droplets without forming said foam.
 17. The system of claim 12 wherein said extinguishant is water, wherein said second means is adapted to mix said water and said combustion products in each of said heads in a manner to atomize said water and form a fog, and wherein, upon said reduction of said circulation, each of said heads is adapted to discharge said water directly towards said fire in a spray of droplets without forming said fog.
 18. The system of claim 12 wherein said third means also changes the spray angle of said discharge.
 19. The system of claim 12 wherein said third means changes the rate of said discharge in response to said additional predetermined fire condition. 